Fan



LT. HOPE.

FAN.

' APPLICATION FILED JUNEIE, 1921.

Patented Jul 4,1922.

Wives-s ATTORNEY JOHN T. HOPE, OF KANSAS CITY, MISSOURI.

I UNITED STATES FAN.

Application filed June 16, 1921.

To all cu/Lom it may concern:

Be 1t known that I, JoHN T. Horn, a

' citizen'of the United States, and resident of Kansas City, county of Jackson, State of lWlissoui-nhave invented a certain new and useful Improvement in Fans, of which the following is a complete specification.

This invention relates to the fans designated primarily for drying .lumber, grain, and the like, and also for ventilating buildings,mines, etc. More particularly the invention relates to that class of fans for circulating large volumes of air under low pressure or vacuum.

The object of the invention is to produce a fan of such construction that it obviates all back lash of air near the hub, as found in the conventional type of fan, and there fore insures a discharge of air for the full length of the fan blades, a fan possessing this advantage obviously having a greater capacity for circulating air than the conventional type of fan of the same size driven under an equal application of power.

More specifically the object is to produce a so-called conical fan having each blade provided with a straight air-cutting edge and a forwardly-bowed discharge edge, with the front portions of the straight edges of the blades overlapping and arranged rearward of the corresponding portions of the discharge edges of the preceding blades, so that said last-named ends of the discharge edges of the blades shall intercept back currents (back-lash) of air and thus insure forward discharge of air for the full lengthradially measured-of the blades.

With the object, therefore, of increasing the capacity and efiiciency of fans, the invention consists in certain novel and useful features of construction and organization of parts as hereinafter described and claimed; and in order that it may be fully understood, reference is to be had to the accompanying drawing, in which:

Figure 1, is a rear elevation of a fan embodying the invention.

Figure 2, is a front elevation of the fan.

Figure 3, is a side elevation of the fan.

Figure 4 is a section on the line IV-IV of Figure 2. I

In the said drawing, 1 indicates a shaft adapted to be driven in any suitable manner, and secured upon the shaft is a fan constructed as follows: 2 is a thimble or hub fitted on the shaft and provided with Specification of Letters Patent.

Patented July 4, 1922.

Serial No. 478,001.

front and rear flanges 3 and 4 respectively,

the last named flange being of conical form, the thimble being made rigid with the shaft a set screw 5 or otherwise.

A series of equi-spaced rearwardly-diverging radial braces .6, are secured at their front endsto the conical flange and at their rear ends to a ring 7, disposed concentrically of the shaft in a plane perpendicular to the latter, and to hold thering rigidly in position, radial braces 8 are secured to the braces 6 and to a collar 9, secured on the shaft in a plane between those occupied by the thimble and ring.

A series of forwardly-bowed braces 10 corresponding in number to braces 6, and occupying planes intersecting those of braces 6, are secured at their rear ends to the ring and at their front ends to the flange 3 of the thimble, it being noted by reference particularly to Figures 1 and 2, that said braces extend tangentially to the flange 3, and that their rear ends are spaced from the corresponding ends of braces 6, and that the front portions of braces 10 therefore overlap the corresponding portions of braces 6.

The fan blades 11 are of substantially truncated-isosceles triangular form in face View. In side view they are bowed forwardly, and so twisted or curved that their cutting edges are straight and their trailing or discharge edges are curved. The cutting edges coincide with and are secured to the straight braces 6 and their discharge edges coincide with and are secured to the braces 10. As a result, the cutting edges of the blades are partly overlapped by the exit or discharge edges of the preceding blades respectively.

In operation the fan turns in the direction indicated by the arrow, (Figure 2), and as the cutting edges out through the air, the forward surfaces of. the blades force the air forward and the hollow sides tend to provide expanding chambers in which the air rearward of the fan tends to rush to avoid the production of a vacuum. As a result of the form and overlapping relation of the blades, the fan has maximum capacity and efficiency, because a check is provided against back-lash and the blades are enabled to discharge air for the full length of their cutting edges.

From the above description it will be apparent that I have produced a device of the character described which possesses all the features of advantage set forth as desirable and while I have described and claimed the preferred embodiment of the same, I reserve the right to make all changes probably fallin within the spirit and scope of the appendzd claims.

What I claim is:

1. A fan comprising a hub and a ring disposed in diflerent parallel planes with their axes alined, and forwardly bowed blades converging forwardly around the common axis of said hub and ring, the cutting edges of the blades being straight and their op osite or discharge edges being outwardly bowed; the front portions of said curved edges of the blades respectively overlapping the corresponding ends of the cutting edges of the following blades, the rear ends ofsaid edges of the blades being spaced apart and said edges from front to rear occupying intersecting planes.

2. A fan comprising a shaft, a thimble secured on the shaft, a collar secured on the shaft rearward of the thirnble, a ring rearward of the collar and concentric with the shaft, forwardly-converging straight braces secured to and extending from the ring to the thimble, and disposed radially of the shaft, forwardly-bowed and converging braces secured to the ring and thirnble forward of the connection with the latter of the first-named braces; each of the bowed braces occupying a plane intersecting the radial plane of one of the first-named braces about midway its length, between the collar and said converging braces, and forwardlyconverging blades secured at their rear ends to said ring, at their front ends to said thimble and at their opposite edges to pairs of said straight and bowed braces, the bowed edges of the blades overlapping and intersecting the planes of the straight edges of the adjacent blades respectively, and s aced at their rear ends from the correspon ing ends of the straight edges of said adjacent blades, respectively.

In witness whereof I hereunto afiix my signature.

JOHN T. HOPE. 

